The solar spectrum that reaches land surface is formed predominantly by ultraviolet (100 to 400 nm), visible (400 to 800 nm) and infrared (above 800 nm) radiations. Ultraviolet radiation (UV) is responsible for the activation of photochemical reactions. The effect of solar radiation on man depends on the individual characteristics of the exposed skin, the intensity of the radiation, and the frequency and time of exposure of the skin to radiation. (Flor, J., et al., “Protetores Solares” Química Nova, v. 30, 2007).
The band of UV radiation can be divided in three parts: UVA (320 to 400 nm), UVB (280 to 320 nm) and UVC (100 to 280 nm) (Flor, J., et al., 2007).
UVA radiation penetrates the dermis and induces the pigmentation of skin, promoting bronzing by means of augmenting the synthesis of melanin. Histologically, UVA radiation also can cause damage to the peripheral vascular system, induce cancer of skin, and in an indirect manner promote formation of free radicals. (Flor, J., et. al., 2007). Over time, it provokes alterations in collagen and elastic fibers, leading to premature aging (Ribeiro, R. P., et al., “Avaliação do Fator de Proteção Solar (FPS) in vitro de produtos comerciais e em fase de desenvolvimento” Revista Infarma, v. 16, 2004).
UVB radiation can promote sunburns (erythemas), bronzing of the skin, and premature aging. UVB radiation is also responsible for the transformation of skin ergosterol to vitamin D. Frequent and intense exposure to UVB radiation can cause breaks in DNA, and suppress the immune response of the skin. In this way, beyond increasing the risk of fatal mutations, manifested in the form of skin cancer, its activity reduces the chance of a malignant cell being recognized and destroyed by the organism (Flor, J., et al., 2007).
The deleterious effects of UV radiation in man can be minimized by the use of UV filters, frequently utilized in cosmetic and dermatological compositions (Flor, et. al., 2007). Currently, UV filters have been developed to provide protection in the bands of UVA and UVB.
There are two classes of UV filters: organic and inorganic, routinely and respectively classified as filters that absorb radiation (chemical filters) and filters that reflect radiation (physical filters). A second and simpler classification is based on organic filters having organic compounds, and inorganic filters having metal oxides.
A study carried out by the American organization EWG (Environmental Working Group), demonstrated that 84% of the tested photoprotective formulations offered inadequate protection to UV radiation. In this sense and the need for preparations with greater efficacy—for example, better efficiency in protection and greater chemical stability—the segment has demanded from large manufacturers to perfect new UV filters (Flor, J., et al., 2007).
To avail a UV filter to the consumer, it is necessary that it incorporates a second ingredient, for example, an excipient. This association of UV filter/second ingredient is denominated a sunscreen or photoprotective composition. Some characteristics are desired so that the sunscreens can be commercialized. Beyond chemistry, photochemistry and thermically inertness the protectors must exhibit other characteristics, as for example, to be nontoxic, not to be sensitizing, irritating or mutagenic, not to be volatile, possess appropriate characteristics of solubility, not to be absorbed by the skin, not to change color, not to stain skin and clothes, to be colorless, to be compatible with formulation and conditioning material and be stable in the final product (Flor, J., et al., 2007).
The preparation of a sunscreen in general has two basic components: active ingredients (organic and/or inorganic filters) and inactive ingredients (for example, excipients). The mixture of inactive ingredients defines the type of vehicle. Various vehicles can be utilized in the preparation of sunscreens, from simple solutions to structures more complex as emulsions (Flor, J., et. al., 2007).
Various methods are related in the literature for the preparation of nanoparticles, which can be classified as: 1) methods based on the in situ polymerization of dispersed monomers; or 2) methods based on the precipitation of pre-formed polymers (Schaffazick, S. R., et al., 2003). The principal the precipitation methods are salting-out (Galindo-Rodriguez, S., et al., “Physicochemical parameters associated with nanoparticle formation in the salting-out, emulsification-diffusion, and nanoprecipitation methods” Pharmaceutical Research, 21, 1428-1439, 2004), emulsification-diffusion (Leroux, J. C., et al., “New approach will be the preparation of nanoparticles by an emulsification-diffusion method” European Journal of Pharmaceutics and Biopharmaceutics, 41, 14-18, 1995), nanoprecipitation and interfacial polymer deposition (Fessi, H., et al., “Nanocapsules formation by interfacial polymer deposition following solvent displacement” International Journal of Pharmaceutics, 55, R1-R4, 1989).
The cosmetic and cosmeceutical industries also have utilized substances coming from flora: phytocosmetics and phytocosmeceuticals. In this sense, with regard to biodiversity, Brazil relies on important ecosystems, including Amazonian, as arsenals of plants with proven or potential uses for the cosmetic industry (Marinho, V. M. C., 2004).
Among these plants include, without limitations, crabwood (andiroba or Carapa guianensis), buriti (Mauritia flexuosa and Mauritia vinifera), cacao (Theobroma cacao), German chamomile (Matricaria recutita, Matricaria chamomilla and Matricaria suaveolens), brazilnut (Bertholletia excelsa), theobroma (Theobroma grandiflorum), guarana (Paullinia cupana), macela (Achyrccline satureioides), passion fruit (Passiflora edulis), mate (Ilex paraguariensis), Surinam Cherry (Eugenia uniflora), murumuru palm (Astrocaryum murumuru), batua palm (Oenocarpus batua), tucuma (Astrocaryum tucuma), coconut (Cocos nucifera L.), peanut (Arachis hypogaea), cotton (Gossypium L.), sesame (Sesamum indicum) and coffee (Coffea arabica), and others.
The pulp of buriti (also known as muriti, and scientific names Mauritia flexuosa and Mauritia vinifera) is basically constituted of fatty acids, tocopherols and carotenoids. After the extraction of the pulp, the composition of the buriti oil presents good stability for long periods of time (Albuquerque, M. L. S., et al., “Characterization of Buriti (Mauritia flexuosa L.) Oil by Absorption and Emission Spectroscopies” J. Braz. Chem. Soc., Vol. 16, No. 6A, 1113-1117, 2005; Pastore Jr., F., et al., “Introdução à Produção de Cosméticos—Uma abordagem teórica e prática com utilização de produtos da flora amazônica” UNB, January 2005).
Japanese patent application 2000319120 describes a cosmetic composition that contains one or more vegetable extracts (among them, extract of buriti) and exhibits properties of prolonged humidity retention of the skin, providing prevention or reduction of diseases of the skin, as, for example, dryness and cracks.
Brazilian patent application PI 0303404-6 contemplates the use of buriti oil in the preparation of cosmetic formulations, as a potentiator of solar protection and source of emollients and antioxidants.